USLC® Columns Put the Right Tools in Your LC Method Development Toolbox - Understanding Selectivity in Reversed Phase Separations – A Simplified Approach to HPLC and UHPLC Column Selection
Column selectivity has the most significant influence on chromatographic peak separation, or resolution, so choosing the right column can greatly speed up HPLC and UHPLC method development. In this article, we discuss column choice and identify a set of just 4 stationary phasesRestek’s USLC® column setthat encompasses the widest range of reversed phase selectivity available today.
Two options for the analysis of PGIs in API have been developed by Merck and Restek to meet different laboratory needs. The first option is a fast method for the analysis of sulfonate esters on the Rxi®-5Sil MS column. The second option is a comprehensive method for the analysis of both sulfonate esters and alkyl halides on the Rtx®-200 column. Both methods require very little sample preparation, which helps increase laboratory productivity.
Restek has developed the first QuEChERS-based method for determining pesticide residues in dietary supplements. This simple, cost-effective procedure reduces matrix interferences as well as sample prep variation among technicians.
Determining Pesticides in Dietary Supplements with QuEChERS Extraction, Cartridge SPE, and GCxGC-TOFMS
The novel approach used here combines QuEChERS extraction, cartridge SPE cleanup, and GCxGC-TOFMS analysis, resulting in good recoveries for a wide range of pesticides in dietary supplements. Matrices include dandelion root, sage, and a multi-herb finished product. (PDF - 394kB)
Restek USLC columns offer the widest range of selectivity available and are an integral part of successful method development. Ideal for column switching systems, these columns provide orthogonal separations to create optimal resolution and robust methods—all in a 4-column set. (PDF - 1813kB)
USLC columns and this guide will help you easily choose the right stationary phase to target nearly any analyte in reversed phase or HILIC method development. It will also help you adjust your mobile phase to further improve results without guesswork or wasted time. (PDF - 1682kB)
Analyze volatile compounds and polar analytes with greater confidence using Rxi-624Sil MS columns. Optimized selectivity, higher inertness, and lower bleed result in reliable separations and accurate, trace-level determinations. Includes environmental and pharmaceutical applications. (PDF - 3111kB)
Unlike C18 columns, Ultra IBD (intrinsically base deactivated) columns can interact in normal phase mode with analytes that possess charged functional groups, providing greater versatility for LC-MS analyses. Excellent peak shape in either normal phase mode or reversed phase mode increases sensitivity and improves quantification. The 4-page note shows example analyses of penicillins and cephalosporins. (PDF - 987kB)
The new Rxi-1301Sil MS column is ideal for the analysis of multiple compound classes across a range of polarities and volatilities. With its cyano-based selectivity and high thermal stability, it is the best 1301-type column for robust MS analyses. (PDF - 2143kB)
Save time and money—let Restek custom blend reference standards specifically for your residual solvent testing needs! (PDF - 76kB)
This 12-page reference includes a review of headspace fundamentals, the revised USP <467> method (July, 2008), chromatography for Procedures A, B, and C, and technical tips for optimization. Guidance on fast, effect method development is given. (PDF - 471kB)